Improved separation performance of SS fiber nonwoven felt by the coating of a non-isotropic porous SS membrane layer

With excellent mechanical properties, large porosity, and permeability, stainless steel (SS) fiber nonwoven felt has outstanding application advantages in high-temperature filtration and purification. However, the pore size of the SS nonwoven felt, which is directly determined by the diameter of the produced fiber stacked inside, usually varies from tens of microns to several microns. Low filtration accuracy greatly limits its application in the fields of fine separation and purification. In this study, the separation performance of SS fiber nonwoven felt was improved by the coating of a non-isotropic porous SS membrane layer via the immersion precipitation phase inversion-sintering method. The effects of sintering temperature on pore structure, surface wettability, separation performance, and mechanical properties of the coated SS nonwoven felt were characterized by scanning electron microscope (SEM), water contact angle (WCA), water permeability, and tensile test, respectively. The results suggest that with the increase of sintering temperature from 1000°C to 1200°C, both porosity and pore size reduce gradually. The WCA value shows an increase from 31.4 to 62.3° and pure water flux shows a corresponding decrease from 2562 to 889 L . m−2 . h−1. The sintering temperature has a negative effect on the mechanical strength of the coated SS fiber nonwoven felt, which is mainly determined by the mechanical properties of the sintered SS fiber nonwoven felt substrate. The coated SS fiber nonwoven felt exhibits a long-term durable separation performance even after frequent combined physical washing and chemical cleaning when applied in the treatment of potato starch wastewater.

Download Full-text

Effect of Sintering Temperature on the Structure and Properties of Attapulgite-Based Nanofibrous Membranes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.1929 ◽

2017 ◽

Vol 898 ◽

pp. 1929-1934

Author(s):

Ye Kai Zhu ◽

Da Jun Chen

Keyword(s):

Specific Surface ◽

Pore Size ◽

Surface Area ◽

Specific Surface Area ◽

Sintering Temperature ◽

Average Pore Size ◽

Pure Water ◽

Water Fluxes ◽

Structure And Properties ◽

Nanofibrous Membranes

Attapulgite (AT)-based nanofibrous membranes (NFMs) were fabricated via a facile papermaking procedure, and the AT-based NFMs were sintered at three different temperatures (240 °C, 400 °C, and 600 °C). The effect of sintering temperature on the structure and properties, such as specific surface area, pore size distribution, porosity, mechanical property, pure water fluxes of AT-based NFMs, were investigated. The results showed that average pore size, total pore volume, and porosity of AT-based NFMs increased with increasing of the sintering temperature, while specific surface area and flexural strength of AT-based NFMs decreased. The optimal sintering temperature for AT-based NFMs was 400 °C. In addition, it was also found that the swelling degree of AT-based NFMs in aqueous solutions was suppressed and the pure water fluxes of AT-based NFMs were improved by sintering process.

Download Full-text

Study on Poly(ether imide)/Amino-Modified Sillica Hybrid Membranes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.789.218 ◽

2014 ◽

Vol 789 ◽

pp. 218-223

Author(s):

Ying Chen ◽

Jun Fen Sun

Keyword(s):

Mechanical Properties ◽

Pure Water ◽

Sol Gel ◽

Morphological Structure ◽

Hybrid Membranes ◽

Water Contact ◽

Sol Gel Process ◽

And Performance ◽

Field Emission Electron Microscopy

Poly (ether imide) (PEI) membrane with many good properties, such as chemical resistance, biocompatibility, good thermal, and mechanical properties, has been widely used in filtration and biomedical applications. SiO2particles containing amine groups can be a good enzyme immobilization carrier. Organic-inorganic hybrids of poly (ether imide) and amino-modified SiO2were in situ prepared via sol-gel process in the presence of tetraethylortho silicate (TEOS) in a mixed solvent of N, N-Dimethylacetamide/1-Methyl-2-pyrrolidone (DMAc/NMP). The effects of casting solution composition on the membrane morphological structure and performance were investigated. The dispersion of the inorganic and organic phase in the nanoscale was possible with addition of (3-aminopropyl) triethoxysilane (APTES) as shown by field emission electron microscopy. Membranes with different ratio of APTES/TEOS have quite different properties. Mechanical properties evaluation such as rupture elongation ration and tensile strength tests of the hybrid membranes were carried out. Fourier transform infrared spectroscopy (FTIR), pure water fluxes and water contact angle of the hybrid membranes were also characterized. The results show that poly (ether imide)/amino-modified SiO2hybrid membranes have high static adsorption capacity for lysozyme (Lys). Moreover, mechanical properties of the hybrid membranes greatly improve compared to pure PEI membranes.

Download Full-text

Fabrication of Mesoporous N-TiO2 Membrane and its Spectral Characteristics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.791 ◽

2009 ◽

Vol 79-82 ◽

pp. 791-794 ◽

Cited By ~ 3

Author(s):

Zhi Zhou ◽

Wei Gang Wang ◽

Wei Huang ◽

Wen Heng Jing ◽

Wei Hong Xing

Keyword(s):

Visible Light ◽

Pore Size ◽

Band Gap ◽

Mechanical Stability ◽

Pure Water ◽

Sol Gel ◽

Spectral Characteristics ◽

Separation And Purification ◽

Alumina Support ◽

Membrane Pore

Ceramic ultrafiltration membrane, pore size from 2 to 50nm, is of growing interest in separation and purification processes because of their higher chemical, thermal and mechanical stability compared to organic membranes. TiO2 mesoporous membranes have gained tremendous popularity due to their photocatalytic activity and because they possess high water flux and chemical resistance. In recent years, visible-light-induced nitrogen-doped titanium dioxide (N-TiO2) materials have been attracted extensive attention. We synthesized asymmetric N-TiO2 membrane based on this material via sol-gel method, in which titanium tetrabutoxide was used as Ti-precursor and formamide as nitrogen resource. A -alumina support with macropores was used and its diameter, thickness and pore size were 28.5 mm, 2.2 mm and 0.10μm, respectively. The alumina supports were pretreated using PVA to prevent permeation of sol into the supports. Sol was coated on this treated supports, and then formed gel under 60°C. The resulting membrane posseses a pore size of 4nm and its pure water permeability is 3.3L/(m2•h•bar). The influences of formamide on the microstructrue and the spectral characteristics were also analyzed by means of BET, UV-vis. As indicated by results, when the molar ratios of formamide and titanium terabutoxide were near 4, the materials had excellent visible light absorption, the absorption band was shifted to about 545nm and the band gap was reduced to 2.65eV. The band gap was 0.55eV less than that of pure TiO2. The membrane has potential application in purifing of micro-polluted surface water under visible-light environment.

Download Full-text

Structure and Properties of PSf Hollow Fiber Membranes with Different Molecular Weight Hyperbranched Polyester Using Pentaerythritol as Core

Polymers ◽

10.3390/polym12020383 ◽

2020 ◽

Vol 12 (2) ◽

pp. 383

Author(s):

Min Liu ◽

Long-Bao Zhao ◽

Li-Yun Yu ◽

Yong-Ming Wei ◽

Zhen-Liang Xu

Keyword(s):

Mechanical Properties ◽

Molecular Weight ◽

Hollow Fiber ◽

Pure Water ◽

Esterification Reaction ◽

Hollow Fiber Membranes ◽

Water Contact ◽

Molecular Weights ◽

Hyperbranched Polyesters ◽

Fiber Membranes

A homologous series of hyperbranched polyesters (HBPEs) was successfully synthesized via an esterification reaction of 2,2-bis(methylol)propionic acid (bis-MPA) with pentaerythritol. The molecular weights of the HBPEs were 2160, 2660, 4150 and 5840 g/mol, respectively. These HBPEs were used as additives to prepare polysulfone (PSf) hollow fiber membranes via non-solvent induced phase separation. The characteristic behaviors of the casting solution were investigated, as well as the morphologies, hydrophilicity and mechanical properties of the PSf membranes. The results showed that the initial viscosities of the casting solutions were increased, and the shear-thinning phenomenon became increasingly obvious. The demixing rate first increased and then decreased when increasing the HBPE molecular weight, and the turning point was 2660 g/mol. The PSf hollow fiber membranes with different molecular weights of HBPEs had a co-existing morphology of double finger-like and sponge-like structures. The starting pure water contact angle decreased obviously, and the mechanical properties improved.

Download Full-text

Ceramic Processing of Silicon Carbide Membranes with the Aid of Aluminum Nitrate Nonahydrate: Preparation, Characterization, and Performance

Membranes ◽

10.3390/membranes11090714 ◽

2021 ◽

Vol 11 (9) ◽

pp. 714

Author(s):

Esra Eray ◽

Victor Manuel Candelario ◽

Vittorio Boffa

Keyword(s):

Silicon Carbide ◽

Pore Size ◽

Mechanical Stability ◽

Sintering Temperature ◽

Pure Water ◽

Aluminum Nitrate ◽

Membrane Properties ◽

Basic Medium ◽

Aluminum Nitrate Nonahydrate ◽

Nitrate Nonahydrate

The development of a low-cost and environmentally-friendly procedure for the fabrication of silicon carbide (SiC) membranes while achieving good membrane performance is an important goal, but still a big challenge. To address this challenge, herein, a colloidal coating suspension of sub-micron SiC powders was prepared in aqueous media by employing aluminum nitrate nonahydrate as a sintering additive and was used for the deposition of a novel SiC membrane layer onto a SiC tubular support by dip-coating. The sintering temperature influence on the structural morphology was studied. Adding aluminum nitrate nonahydrate reduced the sintering temperature of the as-prepared membrane compared to conventional SiC membrane synthesis. Surface morphology, pore size distribution, crystalline structure, and chemical and mechanical stability of the membrane were characterized. The membrane showed excellent corrosion resistance in acidic and basic medium for 30 days with no significant changes in membrane properties. The pure water permeance of the membrane was measured as 2252 L h−1 m−2 bar−1. Lastly, the final membrane with 0.35 µm mean pore size showed high removal of oil droplets (99.7%) in emulsified oil-in-water with outstanding permeability. Hence, the new SiC membrane is promising for several industrial applications in the field of wastewater treatment.

Download Full-text

CHEMICAL CLEANING OF MICROFILTRATION CERAMIC MEMBRANE FOULED BY NOM

Jurnal Teknologi ◽

10.11113/jt.v80.12156 ◽

2018 ◽

Vol 80 (6) ◽

Author(s):

Maisarah Mohamed Bazin ◽

Yuzo Nakamura ◽

Norhayati Ahmad

Keyword(s):

Ceramic Membrane ◽

Sintering Temperature ◽

Ph Value ◽

Pure Water ◽

Water Flux ◽

Chemical Cleaning ◽

Naoh Solution ◽

Membrane Porosity ◽

Pure Water Flux ◽

Ball Clay

Microfiltration membrane made from Sayong ball clay by using uniaxial dry compaction method was used to treat natural organic matter (NOM) source water. A sintering temperature of 900 °C to 1000 °C were applied. The effect of sintering temperature on membrane porosity, strength and water flux were identified. The porosity of the membrane decreased with increasing sintering temperature and the strength and flux increased with temperature. The membrane was subjected to NOM filtration experiments. The results showed an improvement to the quality of permeate water, where there is a reduction in COD, TSS, BOD5, turbidity, hardness and salinity; and an increased pH value. The effect of chemical cleaning on the fouled membrane also was studied. After cleaning with NaOH solution, a high flux recovery was achieved (up to 50% from the initial pure water flux). The degree of cleanliness of fouled membranes after chemical cleaning was further observed with SEM and EDX analysis.

Download Full-text

Microcrystalline Cellulose-Blended Polyethersulfone Membranes for Enhanced Water Permeability and Humic Acid Removal

Membranes ◽

10.3390/membranes11090660 ◽

2021 ◽

Vol 11 (9) ◽

pp. 660

Author(s):

Amirul Islah Nazri ◽

Abdul Latif Ahmad ◽

Mohd Hazwan Hussin

Keyword(s):

Humic Acid ◽

Pore Size ◽

Composite Membrane ◽

Microcrystalline Cellulose ◽

Pure Water ◽

Water Flux ◽

Composite Membranes ◽

Size Exclusion ◽

Inversion Method ◽

Water Contact

A novel polyethersulfone (PES)/microcrystalline cellulose (MCC) composite membrane for humic acid (HA) removal in water was fabricated using the phase inversion method by blending hydrophilic MCC with intrinsically hydrophobic PES in a lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) co-solvent system. A rheological study indicated that the MCC-containing casting solutions exhibited a significant increase in viscosity, which directly influenced the composite membrane’s pore structure. Compared to the pristine PES membrane, the composite membranes have a larger surface pore size, elongated finger-like structure, and presence of sponge-like pores. The water contact angle and pure water flux of the composite membranes indicated an increase in hydrophilicity of the modified membranes. However, the permeability of the composite membranes started to decrease at 3 wt.% MCC and beyond. The natural organic matter removal experiments were performed using humic acid (HA) as the surface water pollutant. The hydrophobic HA rejection was significantly increased by the enhanced hydrophilic PES/MCC composite membrane via the hydrophobic–hydrophilic interaction and pore size exclusion. This study provides insight into the utilization of a low-cost and environmentally friendly additive to improve the hydrophilicity of PES membranes for efficient removal of HA in water.

Download Full-text

Anti-Fouling Performance of Mixed Matrix PVDF Membranes with Mono-Hydroxyl Poly(dimethylsiloxane) (PDMS-OH) Grafted Silica Nanoparticles

10.26434/chemrxiv.13186982 ◽

2020 ◽

Author(s):

MUAYAD AL-SHAELI ◽

Stefan J. D. Smith ◽

Shanxue Jiang ◽

Huanting Wang ◽

Kaisong Zhang ◽

...

Keyword(s):

Pore Size ◽

Silica Nanoparticles ◽

Membrane Fouling ◽

Pure Water ◽

Water Flux ◽

Rejection Rate ◽

Silica Content ◽

Mixed Matrix ◽

Modified Silica ◽

Water Contact

In this study, we investigate the use of surface-modified silica nanoparticles to improve the anti-fouling performance of PVDF ultrafiltration membranes. Here, fouling resistant nanoparticles were prepared by grafting monohydroxy-polydimethylsiloxane onto the surface of silica nanoparticles using Steglich esterification. The mixed matrix PVDF membranes were prepared at a range of nanoparticle concentrations (0, 1.6, 3.2, 6.3, and 11.8%) to understand how PDMS modified silica content affected membrane performance. The resulting hybrid membranes were characterised using a range of techniques including scanning electron microscopy (SEM), water contact angle (CA), porosity, and pore size measurements, in order to determine how morphological features of the nanocomposite membranes affected fouling and pure water flux. Embedding silica nanoparticles resulted in a significant reduction in membrane fouling, including lower protein adsorption and a flux recovery ratio of 97 %. Although water flux was reduced by the addition of nanoparticles, the change in the porosity, mean pore size and the hydrophilicity of the membrane caused the rejection rate to be increased significantly. Together, these results are of particular benefit to the ultrafiltration industry, where improved antifouling and flux recovery can help reduce operating and maintenance costs in these membrane processes.<br><br>

Download Full-text

Anti-Fouling Performance of Mixed Matrix PVDF Membranes with Mono-Hydroxyl Poly(dimethylsiloxane) (PDMS-OH) Grafted Silica Nanoparticles

10.26434/chemrxiv.13186982.v1 ◽

2020 ◽

Author(s):

MUAYAD AL-SHAELI ◽

Stefan J. D. Smith ◽

Shanxue Jiang ◽

Huanting Wang ◽

Kaisong Zhang ◽

...

Keyword(s):

Pore Size ◽

Silica Nanoparticles ◽

Membrane Fouling ◽

Pure Water ◽

Water Flux ◽

Rejection Rate ◽

Silica Content ◽

Mixed Matrix ◽

Modified Silica ◽

Water Contact

Download Full-text

Novel High Flux Poly(m-phenylene isophtalamide)/TiO2 Membranes for Ultrafiltration with Enhanced Antifouling Performance

Polymers ◽

10.3390/polym13162804 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2804

Author(s):

Mariia Dmitrenko ◽

Anna Kuzminova ◽

Andrey Zolotarev ◽

Vladislav Liamin ◽

Tatiana Plisko ◽

...

Keyword(s):

Uv Irradiation ◽

Optimal Transport ◽

Membrane Separation ◽

Pure Water ◽

Cutting Fluid ◽

Separation Performance ◽

Recovery Ratio ◽

High Flux ◽

Water Contact ◽

Tio2 Particles

Wide application of ultrafiltration in different industrial fields requires the development of new membranes with tailored properties and good antifouling stability. This study is devoted to the improvement of ultrafiltration properties of poly(m-phenylene isophtalamide) (PA) membranes by modification with titanium oxide (TiO2) particles. The introduction of TiO2 particles improved membrane separation performance and increased antifouling stability and cleaning ability under UV irradiation. The developed membranes were characterized by scanning electron and atomic force microscopy methods, the measurements of water contact angle, and total porosimetry. The transport properties of the PA and PA/TiO2 membranes were tested in ultrafiltration of industrially important feeds: coolant lubricant (cutting fluid) emulsion (5 wt.% in water) and bovine serum albumin (BSA) solution (0.5 wt.%). The PA/TiO2 (0.3 wt.%) membrane was found to possess optimal transport characteristics in ultrafiltration of coolant lubricant emulsion due to the highest pure water and coolant lubricant fluxes (1146 and 32 L/(m2 h), respectively), rejection coefficient (100%), and flux recovery ratio (84%). Furthermore, this membrane featured improved ability of surface contamination degradation after UV irradiation in prolonged ultrafiltration of BSA, demonstrating a high flux recovery ratio (89–94%).

Download Full-text